Also here is a little fun fact:

I once had a nightmare when I was in 8th grade where I was in a house with a flashlight, running around the house to find an exit when suddenly I got attacked by a mario entity with 7 hands and a head (the entity had no torso or legs) that entity started to chase me down and I quickly jumped out of a window to escape it but I was then attacked by another entity resembling Mario the moment I turned my back (I barely remember how it looked like but it was more human and had an actual body unlike the one that had only had a head and 7 hands attached to it, also it had longer limbs), I woke up after that.

The Harvestman's inspiration comes from the mario entity that was chasing me down on that nightmare inside the house.